Our invention relates generally to telecommunications networks by time division multiplexing, such as those for telephone, facsimile, and other data transmission, and particularly to a time division multiplex telecommunications network having a plurality of input highways each for the time division transmission of two or more channels of data, and a plurality of output highways each for the time division transmission of two or more channels of data. Still more specifically, our invention pertains to means for, and a method of, transferring data in such telecommunications network from any selected channel of any input highway to any selected channel of any output highway.
Time division switching is known whereby a plurality or multiplicity of signals are sent over a common path by using sucessive time intervals for the different signals. We are also aware that time division techniques have been used for channel separation in a telecommunications network having a plurality of input highways and a plurality of output highways. Japanese Laid Open Patent Applications Nos. 54-103608 and 54-103609 both suggest switching systems between such input and output highways, each highway being for the time division transmission of two or more channels.
We object to these and similar prior art time division switching systems because each input highway is provided with as many data memories as there are output highways. The total number of the data memories becomes prohibitive in large telecommunications networks comprised of many input highways and many output highways. Such a large number of data memories have rendered the conventional time division switching systems unnecessarily bulky and expensive.